Skin tends to be more susceptible to wrinkles than any other tissue because of frequent contact with various external stimuli. Particularly, facial skin is directly exposed to environmental factors such as sunlight, dry air and pollutants, and it begins to wrinkle earlier than other skin tissues.
The most characteristic change arising from the aging of skin tissues takes place in the skin matrix. Aging reduces the ability of skin fibroblasts in the dermis to create fiber and matrix components. Generally, a reduction in the amount of matrix leads to a decrease in skin thickness and deterioration of skin elasticity, causing the formation of wrinkles. That is, skin aging causes serious problems, such as elasticity loss, blood circulation disturbance and poor skin barrier function.
UV light exposure generates free radicals, reactive oxygen species (ROS), radical species derived from active carbonyl compounds, etc. in and on the skin. These active species are considered major causes of damage to skin cells. Further, the active species induce DNA damage and attack cell membrane structures, leaving age spots. Moreover, the attack of the active species causes loss of the functions of collagen and fibers to make the skin moist, soft, smooth and elastic, resulting in accelerated wrinkling. The administration of antioxidants for the removal of free radicals may also be helpful in reducing skin wrinkles. However, not all antioxidants exhibit satisfactory effects against skin wrinkling. Direct observation is desirable to better evaluate the effects of antioxidants on the reduction of skin wrinkles. Many drugs and cosmetics are currently being investigated for their potential to reduce skin wrinkles caused by external environmental factors and internal mechanisms.